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cahlen/cfd-chaotic-advection

Chirikov Standard Map Lyapunov Spectrum Maximal Lyapunov exponent Λ(K) for the Chirikov standard map on T², computed with a custom CUDA Benettin kernel on NVIDIA RTX 5090 (sm_120). Part of the bigcompute.science CFD conjecture program — GPU-accelerated exploration of open questions in fluid mixing and dynamical systems. Quick Start from datasets import load_dataset ds = load_dataset("cahlen/cfd-chaotic-advection", "deep_sweep", split="train") row = ds[1200]… See the full description on the dataset page: https://huggingface.co/datasets/cahlen/cfd-chaotic-advection.

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Chirikov Standard Map Lyapunov Spectrum

Maximal Lyapunov exponent Λ(K) for the Chirikov standard map on T², computed with a custom CUDA Benettin kernel on NVIDIA RTX 5090 (sm_120).

Part of the bigcompute.science CFD conjecture program — GPU-accelerated exploration of open questions in fluid mixing and dynamical systems.

Quick Start

python
from datasets import load_dataset

ds = load_dataset("cahlen/cfd-chaotic-advection", "deep_sweep", split="train")
row = ds[1200]
print(f"K={row['K']:.4f}, mean Λ={row['mean_lyapunov']:.6f}")

What's In This Dataset

Each row is one coupling parameter K on a uniform grid in [0, K_max]:

ColumnTypeDescription
k_indexintGrid index
KfloatStandard map coupling parameter
mean_lyapunovfloatMean maximal Lyapunov exponent over ICs
std_lyapunovfloatStandard deviation across ICs
min_lyapunovfloatMinimum over ICs
max_lyapunovfloatMaximum over ICs
fraction_positivefloatFraction of ICs with Λ > 0

Configurations

Confign_kn_icn_itersK_maxTrajectoriesWall time
deep_sweep20488192500005.016,777,216116.6 s
standard_sweep5124096200005.02,097,1525.9 s
smoke_test6451250002.032,768~1 s

Certifying logs are in logs/. Claim-validation artifacts in validation/ (convergence at $K=5$, convergence_k5_gpu.json). Metadata in metadata.json.

Validation artifacts

FileDescription
validation/convergence_k5_gpu.jsonGPU mean Λ at $K=5$ for 5k–100k iterations (65,536 ICs)
validation/lyapunov_k2_ic65536_iter*.csvPer-iteration-count sweeps at $K=0$ and $K=5$ only

Generated by validate_claims.py — see finding claim-validation table.

Key Results (deep_sweep)

  • Λ(0) = 0 (integrable limit validated)
  • At literature K_crit ≈ 0.971635406: mean Λ ≈ 0.0446, >99.9% ICs positive
  • At K = 5: mean Λ ≈ 0.956
  • Zero NaN/Inf across all trajectories

Reproduction

bash
git clone https://github.com/cahlen/idontknow.git
cd idontknow
./scripts/experiments/cfd-chaotic-advection/run.sh 2048 8192 50000 5.0

CUDA kernel: cahlen/bigcompute-cuda-kernels (cfd-chaotic-advection/standard_map_lyapunov.cu)

Related

Citation

bibtex
@misc{humphreys2026cfdchaoticadvection,
  author = {Humphreys, Cahlen},
  title = {Chirikov Standard Map Lyapunov Spectrum (GPU-Computed)},
  year = {2026},
  publisher = {Hugging Face},
  howpublished = {\\url{https://huggingface.co/datasets/cahlen/cfd-chaotic-advection}}
}

Human–AI collaborative research. Not peer-reviewed. All code and data open for verification.